Dual purpose electroactive copolymers

ABSTRACT

Multifunctional electroactive copolymers are provided. The copolymers may be A-B-A triblock copolymers, brush-type graft copolymers, or variations thereof. In a preferred embodiment, the copolymers are “dual use” in that they comprise both a light emitting segment and a charge transport segment. Methods of synthesizing the novel electroactive copolymers are provided as well, as are opto-electronic devices, particularly LEDs, fabricated with the novel copolymers.

TECHNICAL FIELD

[0001] This invention relates generally to electroactive polymers. Moreparticularly, the invention pertains to dual purpose electroactivecopolymers, preparation thereof, and use in the manufacture of varioustypes of opto-electronic devices.

BACKGROUND

[0002] Electroactive polymers are frequently used in a number of opticaland electronic applications such as in light emitting diodes (“LEDs”),photovoltaic energy converters, photodetectors, photoconductors, e.g.,in electrophotography, and in chemical and biochemical sensors. In eachof these applications, it is often necessary to use a multiplicity ofelectroactive polymeric materials each having a different function inthe device. For example, different polymeric materials are normally usedto provide electron and/or hole charge transport, luminescence,photo-induced charge generation, and charge blocking or storage. Byworking with a number of structurally and functionally distinctpolymers, one can achieve optimization of these separate functions.

[0003] It would be desirable, however, to reduce the number of polymericmaterials needed in any particular opto-electronic device. In this way,the manufacture of opto-electronic devices is simplified by reducing thetime, cost and number of materials involved in device fabrication.

[0004] The present invention is addressed to the aforementioned need inthe art. A new class of electroactive polymers is now provided,comprising copolymers in which discrete and functionally unique segmentspresent in a single polymer render the polymer multifunctional innature. In a preferred embodiment, the electroactive copolymers are“dual use” polymers by virtue of containing both a charge transportsegment and a light emissive segment. The invention represents animportant advance in the art, insofar as the number of polymericmaterials previously required in the manufacture of opto-electronicdevices may now be significantly reduced. That is, with the presentinvention, fewer discrete and functionally unique polymeric layers arenow necessary to provide all of the desired functions, e.g., electrontransport, hole transport, light emission, and the like.

SUMMARY OF THE INVENTION

[0005] Accordingly, it is a primary object of the invention to addressthe above-mentioned need in the art by providing a dual purposeelectroactive copolymer useful in the manufacture of an opto-electronicdevice.

[0006] It is another object of the invention to provide such a copolymerwhich comprises a charge transporting polymeric segment and a lightemitting polymeric segment.

[0007] It is still another object of the invention to provide such acopolymer in the form of an A-B-A triblock copolymer.

[0008] It is yet another object of the invention to provide such acopolymer in the form of a brush-type graft copolymer.

[0009] It is an additional object of the invention to provide methodsfor synthesizing dual use electroactive polymers as disclosed andclaimed herein.

[0010] It is still an additional object of the invention to provideopto-electronic devices, particularly LEDs, fabricated with a dual useelectroactive copolymer as disclosed and claimed herein.

[0011] Additional objects, advantages and novel features of theinvention will be set forth in part in the description which follows,and in part will become apparent to those skilled in the art uponexamination of the following, or may be learned by practice of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 schematically illustrates preparation of an end cappinginitiator and two macromolecular end capping reagents, as described inExamples 1, 2 and 3, respectively.

[0013]FIG. 2 schematically illustrates preparation of a macromolecularend capping reagent and a macromolecular initiator, as described inExamples 4 and 5, respectively.

[0014]FIG. 3 schematically illustrates macromolecular initiationreactions as described in Examples 6 and 7.

[0015]FIG. 4 schematically illustrates the macromolecular end cappingreaction described in Example 8, part (a).

[0016]FIG. 5 schematically illustrates the macromolecular end cappingreaction described in Example 8, part (b).

[0017]FIG. 6 schematically illustrates preparation of a radicalinitiating condensation monomer, as described in Example 9, parts (a)and (b).

[0018]FIG. 7 schematically illustrates preparation of polystyrenegrafted on “Br2BTFLUO” as described in Example 9, part (c).

[0019]FIG. 8 schematically illustrates the Yamamoto polymerizationreaction described in Example 9, part (d).

[0020]FIG. 9 schematically illustrates the macromolecular initiatedradical polymerization reaction described in Example 9, part (e).

[0021]FIG. 10 is a cross-sectional view of an embodiment of alight-emitting device as may be prepared using the electroactivecopolymers of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0022] Overview and Definitions

[0023] Before describing the present invention in detail, it is to beunderstood that this invention, unless otherwise indicated, is notlimited to specific compositions, components or process steps, as suchmay vary. It is also to be understood that the terminology used hereinis for the purpose of describing particular embodiments only, and is notintended to be limiting.

[0024] It must be noted that, as used in this specification and theappended claims, the singular forms “a,” “an,” and “the” include pluralreferents unless the context clearly dictates otherwise. Thus, forexample, reference to “a polymeric segment” includes more than onepolymeric segment, reference to “a layer” or “a polymeric layer”includes multiple layers, reference to “a reagent” includes mixtures ofreagents, and the like.

[0025] In describing and claiming the present invention, the followingterminology will be used in accordance with the definitions set outbelow.

[0026] The term “polymer” is used to refer to a chemical compound thatcomprises linked monomers, and that may or may not be linear. Theelectroactive copolymers of the present invention generally comprise atleast about 20 monomer units, preferably at least about 50 monomerunits, and generally fewer than about 200 monomer units, preferablyfewer than about 150 monomer units.

[0027] The term “electroactive” as used herein refers to a material thatis (1) capable of transporting, blocking or storing charge (either + or−), (2) luminescent, typically although not necessarily fluorescent,and/or (3) useful in photo-induced charge generation.

[0028] The term “alkyl” as used herein refers to a branched orunbranched saturated hydrocarbon group of 1 to 24 carbon atoms, such asmethyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, octyl,decyl, tetradecyl, hexadecyl, eicosyl, tetracosyl and the like, as wellas cycloalkyl groups such as cyclopentyl, cyclohexyl and the like. Theterm “lower alkyl” intends an alkyl group of one to six carbon atoms,preferably one to four carbon atoms.

[0029] The term “alkenyl” as used herein refers to a branched orunbranched hydrocarbon group of 2 to 24 carbon atoms containing at leastone double bond, typically containing one to six double bonds, moretypically one or two double bonds, e.g., ethenyl, n-propenyl, n-butenyl,octenyl, decenyl, and the like, as well as cycloalkenyl groups such ascyclopentenyl, cyclohexenyl and the like. The term “lower alkenyl”intends an alkenyl group of two to six carbon atoms, preferably two tofour carbon atoms.

[0030] The term “alkynyl” as used herein refers to a branched orunbranched hydrocarbon group of 2 to 24 carbon atoms containing at leastone triple bond, e.g., ethynyl, n-propynyl, n-butynyl, octynyl, decynyl,and the like, as well as cycloalkynyl groups such as cyclooctynyl,cyclononynyl, and the like. The term “lower alkynyl” intends an alkynylgroup of two to six carbon atoms, preferably two to four carbon atoms.

[0031] The term “alkoxy” as used herein refers to a substituent —O—Rwherein R is alkyl as defined above. The term “lower alkoxy” refers tosuch a group wherein R is lower alkyl.

[0032] The terms “aryl” and “aromatic,” as used herein, and unlessotherwise specified, refer to an aromatic moiety containing one to sevenaromatic rings. For aryl groups containing more than one aromatic ring,the rings may be fused or linked. Aryl groups are optionally substitutedwith one or more substituents per ring; suitable substituents include,for example, halo, haloalkyl, alkyl, alkenyl, alkynyl, alkoxy,alkoxycarbonyl, carboxy, nitro, cyano and sulfonyl. The term “aryl” isalso intended to include heteroaromatic moieties, i.e., aromaticheterocycles. Generally the heteroatoms will be nitrogen, oxygen orsulfur.

[0033] The term “arylene” as used herein, and unless otherwisespecified, refers to a bifunctional aromatic moiety containing two toseven aromatic rings that are either fused or linked. Arylene groups areoptionally substituted with one or more substituents per ring; as above,suitable substituents include halo, haloalkyl, alkyl, alkenyl, alkynyl,alkoxy, alkoxycarbonyl, carboxy, nitro, cyano and sulfonyl.

[0034] The term “halo” is used in its conventional sense to refer to achloro, bromo, fluoro or iodo substituent. In the compounds describedand claimed herein, halo substituents are generally bromo, chloro oriodo, preferably bromo or chloro. The terms “haloalkyl,” “haloaryl” (or“halogenated alkyl” or “halogenated aryl”) refer to an alkyl or arylgroup, respectively, in which at least one of the hydrogen atoms in thegroup has been replaced with a halogen atom. “Optional” or “optionally”means that the subsequently described circumstance may or may not occur,so that the description includes instances where the circumstance occursand instances where it does not. For example, the phrase “optionallysubstituted” means that a non-hydrogen substituent may or may not bepresent, and, thus, the description includes structures wherein anon-hydrogen substituent is present and structures wherein anon-hydrogen substituent is not present.

[0035] The invention thus provides electroactive copolymers thatcomprise both a charge transporting polymeric segment and a lightemitting polymeric segment. The presence of these discrete andfunctionally unique segments in a single polymer molecule renders thecopolymer multifunctional in nature (i.e., “dual purpose” at a minimum),insofar as the copolymer is both luminescent, i.e., light emitting, andcapable of transporting charge, either positive or negative.

[0036] Triblock Copolymers

[0037] In one embodiment, the novel copolymers are A-B-A triblockcopolymers, in which one of A and B is a charge transporting polymericsegment and the other is a light emitting polymeric segment. Preferably,it is each A block that is a charge transporting polymeric segment,while the B block is a light emitting polymeric segment.

[0038] The monomer units present in the charge transporting polymericsegment are selected to correspond to the intended use of the polymer.When the charge transporting segment is to be hole transporting, themonomer units in the segment are preferably arylamines, e.g.,triphenylamine, diphenyltolylamine, tetraphenyl-p-phenylene diamine,tetraphenylbenzidine, an arylamine-containing polynuclear aromaticand/or heteroaromatic compound, or a diarylamine such as anN-substituted carbazole or an aminobenzaldehyde hydrazone. When thecharge transporting segment is to be an electron transporting segment,i.e., when the copolymer is used as an electron transport layer in anLED, photoconductor or the like, the monomer units are preferablyelectron deficient moieties that are “conjugated” in the polymerstructure, and include heterocyclic and/or nonheterocyclic aromaticgroups, e.g., aryl sulfones (e.g., biphenyl sulfone), aryl sulfoxides,fluorinated aryls (such as bis(diphenylhexafluoropropane) andoctafluorobiphenyl), biphenyls, diaryl phosphine oxides, benzophenones,1,2,3-triazole, 1,2,4-triazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole(azoxime), 1,2,5-oxadiazole (furazan), 1,3,4-oxadiazole,3,5-diaryl-1,2,4-oxadiazole, 3,4-diaryl- 1,2,5-oxadiazole, 2,5-diaryl-1,3,4-oxadiazole, 1,4-oxazine, 1,2,5-oxathiazine, thiophene,benzothiophene, pyridines, quinolines (including quinoline andisoquinoline), quinoxalines, and pyrimidines.

[0039] The monomer units in the light emitting polymeric segment arearomatic or heteroaromatic, and include polycyclic aromatic moietiesthat are typically although not necessarily fluorescent. These monomerunits include without limitation benzene, naphthalene, anthracene,phenanthrene, indene, pyrene, perylene, phenalene, coronene,fluorescein, fluorene, substituted fluorene, and the like. Exemplarymonomers for forming the light emitting polymeric segment are those thathave previously been disclosed in co-pending, commonly assigned U.S.patent application Ser. No. 08/888,172, filed Aug. 27, 1997, entitled“Polymeric Light-Emitting Device,” as useful for forming an emissivelayer, e.g., in an LED. Those monomers include: dihalo-fluoreneoptionally substituted with one or more substituents other (i.e.,non-halogen substituents) such as phenyl, benzyl, phenoxy, benzyloxy,lower alkyl or lower alkoxy, preferably at but not restricted to the9-position, e.g., 9,9-dialkylfluorene and 9,9-diphenylfluorene; anddihaloanthracene optionally substituted with one or more of theaforementioned substituents, e.g., 9,10-, 2,6-, 1,8- or1,4-dihaloanthracene or dihalodiphenylanthracenes. Aromatic dyes, e.g.,coumarins, rhodamines, pyrans, or the like may also serve as monomerunits in the light emitting polymeric segment, for example, to provide acopolymer that can be used as a photoconductive sensitizer.

[0040] A-B-A triblock copolymers of the invention, wherein A is a chargetransporting polymeric segment and B is a light emissive polymericsegment, may be synthesized using either of two techniques. A firstsynthetic method comprises: (a) contacting a dihalo-substitutedpolycyclic aromatic reactant with a haloaryl moiety also containing aliving free radical polymerization initiator under conditions effectiveto bring about condensation polymerization, resulting in a lightemitting polymeric intermediate comprised of linked polycyclic aromaticmonomer units and two or more displaceable termini; and (b)synthesizing, at each of the termini of the intermediate prepared instep (a), a charge transport segment comprised of polymerized monomerunits. The polymeric end-capping reagents prepared in step (b) arepreferentially synthesized via living free radical polymerization. Part(a) of the method may be shown schematically as follows:

[0041] In the above scheme, compound (I) is the dihalo-substitutedpolycyclic aromatic reactant, wherein Hal represents a halogen atom,typically chloro or bromo, and X is an aromatic or heteroaromatic moietyas explained earlier herein. That is, X is generally although notnecessarily fluorescent, and may be, for example, benzene, naphthalene,anthracene, phenanthrene, indene, pyrene, perylene, phenalene, coronene,fluorescein, fluorene, substituted fluorene, and the like. In apreferred embodiment, X is fluorene substituted with one or moresubstituents such as phenyl, benzyl, phenoxy, benzyloxy, lower alkyl orlower alkoxy, preferably but not necessarily at the 9-position, as in9,9-dialkylfluorene and 9,9-diphenylfluorene. Compound (II) is a livingfree radical polymerization initiator, in which the free radical R. iscapable of end capping the polymerization of (I), and R¹ and R² are eachindependently alkyl or aryl, including substituted and unsubstitutedalkyl and aryl, wherein the substituents are, for example, cyano,carboxyl, and the like, or R¹ and R² together form an optionallyalkyl-substituted cycloalkyl ring containing 4 to 7, typically 5 or 6,carbon atoms. No hydrogen atoms should be present on the carbon atomsadjacent to N in the —NR¹R² group. Suitable R groups are alkyl, aryl,aryl-substituted alkyl, although preferred R groups comprise halogenatedaryl moieties. Examples of specific R groups include phenyl, substitutedphenyl (particularly halogenated phenyl such as p-bromophenyl andp-chlorophenyl), benzyl, substituted benzyl (particularly halogenatedbenzyl), lower alkyl, particularly methyl and tertiary butyl, andcyanoisopropyl. In general the structure of R will be of the formula

[0042] wherein R′, R″ and R′″ are the same or different and are selectedfrom the group consisting of hydrogen, alkyl, halogenated alkyl, phenyl,halogenated phenyl, benzyl, and halogenated benzyl. Suitable living freeradical polymerization initiators are derivatives of2,2,6,6-tetramethyl-1-piperidinyloxy (“TEMPO”), having the structuralformula

[0043] wherein R′ is as defined above, and Q is halogen, preferablychloro or bromo. The “TEMPO” moiety itself has the structural formula

[0044] The polymeric intermediate (III) comprises a light emittingpolymeric segment represented by —[X]_(n)]—and having two displaceabletermini

[0045] deriving from the nitroxyl groups of the polymerizationinitiator.

[0046] The reaction illustrated in Scheme 1 is preferably conducted inthe presence of a catalyst, preferably a nickel catalyst. Exemplarynickel catalysts include ligand-substituted Ni (0) complexes andligand-substituted Ni (II) complexes that generate Ni (0) in situ; itmay be desirable to use a reducing agent such as Zn with the latterclass of catalysts. Particularly preferred nickel catalysts include bis(1,5-cyclooctadiene) nickel (0) and nickel carbonyl tris(triphenylphosphine) nickel (0).

[0047] Step (b) of the reaction, wherein polymer blocks are synthesizedat the termini of the intermediate (III), may be representedschematically as follows:

[0048] Polymerization of the vinyl moiety (IV), i.e., CH₂=CY¹Y², at thetermini of intermediate (III) results in two conjugated terminal blocks,each of which is bound to the central segment, to provide the “A-B-A”triblock structure (V). In this process, the nitroxyl-terminatedintermediate (III) serves as an initiator for the living free radicalpolymerization of the vinyl monomer (IV). The molecular moieties Y¹ andY², which may be the same or different, are either electron-deficient orelectron-rich monomer units that provide a vinyl polymer followinginitiation of polymerization, as discussed above. That is, Y¹ and Y² aretypically heterocyclic and/or nonheterocyclic aromatic groups, e.g.,aryl sulfones (e.g., biphenyl sulfone), aryl sulfoxides, fluorinatedaryls (such as bis(diphenylhexafluoropropane) and octafluorobiphenyl),biphenyl, a diaryl phosphine oxide, a benzophenone, 1,2,3-triazole,1,2,4-triazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole (azoxime),1,2,5-oxadiazole (furazan), 1,3,4-oxadiazole,3,5-diaryl-1,2,4-oxadiazole, 3,4-diaryl-1,2,5-oxadiazole,2,5-diaryl-1,3,4-oxadiazole, 1,4-oxazine, 1,2,5-oxathiazine,benzothiophene, thiophene, pyridine, a quinoline (including quinolineand isoquinoline), a quinoxaline, a pyrimidine, or the like. When thecharge transporting segment is to be hole transporting, the monomerunits in the segment are preferably arylamines, e.g., triphenylamine,diphenyltolylamine, tetraphenyl-p-phenylene diamine,tetraphenylbenzidine, an arylamine-containing polynuclear aromaticand/or heteroaromatic compound, or a diarylamine such as anN-substituted carbazole or an aminobenzaldehyde hydrazone. In thetriblock copolymer product (V), m is typically in the range ofapproximately 10 to 200, preferably 10 to 100, while n is generally inthe range of approximately 2 to 50, preferably 6 to 50.

[0049] An alternative synthetic route to these A-B-A triblock copolymersinvolves (a) contacting a unimolecular living free radicalpolymerization initiator with a polymerizable reactant underpolymerization conditions, wherein the initiator, the reactant, and thepolymerization conditions are effective to provide a charge transportingpolymeric intermediate comprised of a plurality of linked monomer unitsand a single reactive terminus; and (b) catalytically polymerizing adihalo-substituted polycyclic aromatic reactant in the presence of thecharge transporting polymeric intermediate, whereby a light emittingpolymeric segment comprised of linked polycyclic aromatic monomer unitsis formed, with two or more charge transporting polymeric segments boundthereto. This may be shown schematically as follows:

[0050] The unimolecular living free radical polymerization initiator isshown at (IIA), wherein R¹ and R² are as defined earlier herein andwherein R* is identical to R but contains a reactive site that enablesbinding of an additional moiety, as carried out in step (b). Thepolymerizable reactant is shown at (IV), wherein Y¹ and Y² are asdefined earlier herein as well. The reaction forms a monofunctionalizedpolymeric charge transporting block, i.e., the charge transportingpolymeric intermediate (VI), comprised of a plurality of linked monomerunits “—CH₂—C(Y¹Y²)—” and a single reactive terminus R*. Step (b) may berepresented as follows:

[0051] In step (b), the charge transporting polymeric intermediatehaving the single reactive terminus, i.e., structure (VI), is caused toreact with a dihalo-substituted polycyclic aromatic reactant (I),wherein Hal and X are as defined above, in the presence of a suitablecatalyst, preferably a nickel catalyst such as bis (1,5-cyclooctadiene)nickel (0). The reaction results in a triblock copolymer shown at (V) inwhich the central block is a light emitting polymeric segment comprisedof linked aromatic monomer units, and the outer blocks are chargetransporting polymeric segment comprised of electron-deficient orelectron-rich monomeric moieties.

[0052] Brush-Type Graft Copolymers

[0053] In another embodiment, the novel copolymers are brush-type graftcopolymers. It will be appreciated by those skilled in the art that“brush-type” graft copolymers are polymers comprised of a backbonepolymer chain to which are attached a plurality of pendant polymerchains, with the attached (or “grafted”) pendant polymer chainschemically distinct from the backbone polymer chain. In the brush-typecopolymers of the invention, the backbone segment of the copolymer has afirst property and the pendant chains have other properties. Preferably,the backbone is light emitting and the pendant chains are chargetransporting, or vice versa. The monomer units in the chargetransporting polymeric segments are as set forth with respect to theA-B-A triblock copolymers described in the preceding section. That is,when the charge transporting segment is to be hole transporting, themonomer units are preferably arylamines, while when the transportingsegment is to be electron transporting, the monomer units are conjugatedaromatic moieties, e.g., oxazines, oxathiazenes, thiophenes,oxadiazoles, and the like. The monomer units in the light emittingpolymeric segment are also as set forth with regard to the A-B-Atriblock copolymers, i.e., they are polycyclic aromatic moieties thatare typically although not necessarily fluorescent. In this case,however, a fraction of the aromatic monomers that are polymerized toform the polymer backbone are provided with branch points that enablesynthesis of the pendant, “grafted” polymer chains. Thus, for example,to prepare brush-type copolymers having a light emitting backbone andcharge transporting pendant chains, one would carry out the reactionshown in Scheme 1 but add in polymerizable monomers Hal-[Z]-Hal whereinZ is identical to X but includes a reactive site enabling branching. Aspecific example of such a reaction is illustrated comprehensively inFIG. 3, wherein a first monomer is a 9,9-alkyl-substituted fluorene anda second monomer is a functionalized 9,9-di-substituted fluorene asshown, resulting in a backbone containing both such monomers, whereinthe functionalized 9,9-di-substituted monomer units enable preparationof additional polymeric segments at the 9-position of those monomers inthe polymer chain.

[0054] It will be appreciated by those skilled in the art that thepresent methodology can be used to prepare combinations of copolymertypes, e.g., brush-type polymers having pendant chains that arebranched, brush-type polymers containing copolymeric pendant chains,A-B-A triblock copolymers in which the A blocks are provided withpendant chains, and the like. Such modifications of the basic polymersand processes disclosed herein are within the scope of the presentinvention.

[0055] Opto-Electronic Device

[0056] The devices that may be fabricated using the presentelectroactive copolymers synthetic methods include LEDs, photovoltaiccells, photoconductors, photodetectors, and chemical and biochemicalsensors. A primary application of the present invention is in thefabrication of LEDs, semiconductor devices that convert electricalenergy into electromagnetic radiation and are suitable for use asillumination sources, in displays and in indicator lamps.

[0057]FIG. 10 illustrates an LED prepared using the composition andmethod of the invention. A charge transporting and emissive layer 2comprises an electroactive copolymer of the invention and is sandwichedbetween and contiguous with opaque electrode 4 and transparent electrode6. The device is supported on a glass base 8. When a voltage is appliedto electrodes 4 and 6, electrons and holes are injected from oppositeelectrodes, and light is emitted from layer 2 which then radiates fromthe device through transparent electrode 6 and glass base 8. Theelectrodes 4 and 6 comprise a conductive material. Suitable opaqueelectrodes can comprise gold, aluminum, copper, silver or alloys thereofSuitable transparent electrodes comprise, for example, indium tin oxide,polyaniline or polythiophene.

[0058] Such a device is conveniently fabricated by dissolving a dual usepolymer as provided herein in a suitable solvent, e.g., p-xylene,toluene, or the like, and casting a film of the polymer solution on oneof the electrodes. The polymer film is then cured using conventionalmeans. Alternatively, the dual use polymer can be synthesized on asubstrate such as an electrode surface using the synthetic processordiscussed in detail herein. Subsequent layers can be provided in asimilar manner, if desired. In the final fabrication step, the secondelectrode is formed or deposited on the exposed cured surface.

[0059] It is to be understood that while the invention has beendescribed in conjunction with the preferred specific embodimentsthereof, that the foregoing description as well as the examples whichfollow are intended to illustrate and not limit the scope of theinvention. Other aspects, advantages and modifications within the scopeof the invention will be apparent to those skilled in the art to whichthe invention pertains.

[0060] All patents, patent applications, and publications mentionedherein are hereby incorporated by reference in their entireties.

EXPERIMENTAL

[0061] The following examples are put forth so as to provide those ofordinary skill in the art with a complete disclosure and description ofhow to prepare and use the oligomers and polymers disclosed and claimedherein. Efforts have been made to ensure accuracy with respect tonumbers (e.g., quantities, temperature, etc.) but some errors anddeviations should be accounted for. Unless indicated otherwise, partsare parts by weight, temperature is in ° C. and pressure is at or nearatmospheric. Additionally, all starting materials were obtainedcommercially or synthesized using known procedures.

[0062] Instrumentation

[0063] The synthesized compounds were identified by their ¹H and ¹³C-NMRspectra obtained on a Bruker AF 250 Spectrometer. Melting points weredetermined using a Gallenkamp melting point apparatus and areuncorrected. UV-visible and fluorescence spectra were obtained with aHewlett Packard 8452A diode array spectrophotometer and an SAInstruments FL3-11 Fluorometer, respectively. Thermogravimetric analysis(TGA) and Differential Scanning Calorimeter (DSC) of the polymers wereperformed under a nitrogen atmosphere at a heating rate of 10° C./minwith a Perkin Elmer TGS-2 and a DuPont 2100 analyzer, respectively. AWaters 150-C Gel Permeation Chromatograph was used to determinemolecular weights of the polymers which are based on poly(styrene)standards.

EXAMPLE 1 Synthesis of an End-Capping Initiator

[0064]1-(4′-bromophenyl)-1-(2″,2″,6″,6″-tetramethyl-1-piperidinyloxy)ethyl, 1(FIG. 1): To a solution of p-bromostyrene, (25.0 g, 137 mmol) and2,2,6,6-tetramethylpiperidinyloxy (TEMPO) (21.3 g, 137 mmol) in 1:1toluene/ethanol (1000 mL) was added[N,N′-bis(3,5-di-t-butylsalicylidene)-1,2-cyclohexanediaminato]manganese(III) chloride (13.0 g, 20.5 mmol). The reaction mixture wasthen stirred at room temperature for 12 hours, evaporated to dryness,partitioned between dichloromethane (3×200 mL) and water (400 mL), andthe aqueous layer further extracted with dichloromethane (3×200 mL). Thecombined organic layers were then dried, evaporated to dryness, and thecrude product purified by flash chromatography eluting with 1:9dichloromethane/hexane gradually increasing to 2:1dichloromethane/hexane. The desired bromo-substituted alkoxyamine, 1,was obtained as a white solid, mp. 45-46° C. Yield 72%; ¹H NMR (CDCl₃)δ: 0.60, 0.95, 1.09, 1.21 (each br s, 12H, CH₃), 1.24-1.58 (m, 6H CH₂),1.42 (d, J=4 Hz, 3H, CH₃), 4.71 (Abq, J=4 Hz, 1 H. CH), and 7.10 and7.20 (Abq, J=8 Hz, 4 H, ArH); ¹³C NMR (CDCl₃): δ17.20, 20.35, 23.52,34.21, 34.43, 60.08, 82.66, 127.30, 128.32, 135.86, and 146.17; massspectrum (EI) m/z 339/341 (1:1).

EXAMPLE 2 Synthesis of a Macromolecular End Capper

[0065] Polymerization of 4-vinyltriphenylamine with 1 to provide P1(FIG. 1): A mixture of the bromo-substituted alkoxyamine 1 (9.50 g, 1.5mmol) and 4-vinyltriphenylamine (9.97 g, 36.8 mmol, 25 equivalents) wasdissolved in chlorobenzene (10 mL) and the reaction mixture heated at125° C. for 24 hours. The viscous solution was then precipitated twiceinto methanol (500 mL) followed by redissolution into dichloromethane(25 mL) and precipitation into hexane (500 mL). The purified polymer wascollected by vacumn [sic] filtration and dried to give thebromo-phenyl-terminated poly(vinyltriphenylamine) as an off-white solid(7.78 g, 74%); ¹H NMR (CDCl₃): δ0.95-1.20 (minor peaks due to TEMPO endgroup), 1.40-2.20 (m, 3H, CH and CH₂ of backbone) and 6.50-7.20 (m, 14H, ArH); GPC (Pst equivalent Mn=2300, PDI=1.22).

EXAMPLE 3 Synthesis of a Macromolecular End Capper

[0066] Polymerization of N-vinylcarbazole with 1 to provide P2 (FIG. 1):A mixture of the bromophenyl-substituted alkoxyamine 1 (0.50 g, 1.5mmol) and N-vinylcarbazole (7.10 g, 36.8 mmol. 25 equivalents) wasdissolved in chlorobenzene (7.0 mL) and the reaction mixture heated at125° C. for 24 hours. The viscous solution was then precipitated twiceinto methanol (500 mL) followed by redissolution into dichloromethane(25 mL) and precipitation into hexane (500 mL). The purified polymer wascollected by vacuum filtration and dried to give thebromophenyl-terminated poly(vinylcarbazole) as an off-white solid (5.92g, 78%); ¹H NMR (CDCl₃): δ0.95-1.20 (minor peaks due to TEMPO endgroup), 1.40-2.20 (m, 3 H, CH and CH₂ of backbone) and 6.10-7.20 and7.50-8.00 (m, 8 H, ArH); GPC PSt equivalent Mn=2000, PDI=1.28).

EXAMPLE 4 Synthesis of a Macromolecular End Capper

[0067] Polymerization of 2-styryl-5-p-methylphenyloxadiazole with 1 toprovide P3 (FIG. 2): A mixture of the bromo-substituted alkoxyamine 1(0.50 g, 1.5 mmol) and 2-styryl-5-p-methylphenyloxadiazole (7.70 g, 29.4mmol, 20 equivalents) was dissolved in chlorobenzene (7.5 mL) and thereaction mixture heated at 125° C. for 16 hours. The viscous solutionwas then precipitated twice into methanol (500 mL) followed byredissolution into dichloromethane (25 mL) and precipitation into hexane(500 mL). The purified polymer was collected by vacumn filtration anddried to give the bromophenyl-terminated poly(oxadiazole) as anoff-white solid (6.64 g, 81%); ¹H NMR (CDCl₃) δ0.90-1.20 (minor peaksdue to TEMPO end group), 1.40-2.20 (m, 3 H, CH and CH₂ of backbone),2.40 (br s, 3 H. CH₃), and 6.50-7.20 and 7.40-8.00 (m, 8 H, ArH); GPC(PSt equivalent Mn=2800, PDI=1.18).

EXAMPLE 5 Synthesis of a Macromolecular Initiator

[0068] Preparation of poly(di-n-hexylfluorene) end capped withalkoxyamine substituents P4 (FIG. 2): A Schlenk tube containing 700mg(2.54 mmol) of bis(1,5-cyclooctadiene) nicket(0), 450 mg (2.9) mmol)of 2,2′-bipyridyl,) 0.2 mL of 1,5-cyclooctadiene, 6 mL of dry DMF and 6mL of dry toluene was heated under Argon to 80° C. for 0.5 hr. Then 554mg(1.125 mmol) of 2,7-dibromo-9,9-di-n-hexylfluorene and 132 mg(.3875mmol) of the bromoarylalkoxyamine 1 dissolved in 6 mL of degassedtoluene were added under argon to the dark blue reaction mixture. Uponaddition of the monomers, the color turned to reddish-brown and theviscosity increased. After heating for 1 day in the dark, the hotpolymer solution was precipitated into a solution of 100 mL conc. HCL,100 mL of methanol, and 100 mL of acetone. After isolating the crudeproduct via filtration, the alkoxyamine capped polymer wasreprecipitated into a mixture of acetone and methanol for furtherpurification: Mn=5000, PDI=1.8; ¹H NMR (CDCl₃) δ7.4-8 (multiplet,aromatic protons), 2.05 (br singlet, (α-methylene protons of hexylgroups), 1.9 (multiplet, remaining—CH₂—signals of the n-hexylsubstituents) and 0.8 (multiplet, −CH₃).

EXAMPLE 6 Macromolecular Initiation

[0069] Polymerization of TEMPO-functionalized poly(fluorene) withstyrene, P5 (FIG. 3): A mixture of the alkoxyamine-substitutedpoly(fluorene) P4 (Mn=5,000, PDI=1.80), (0.25 g, 0.05 mmol) and styrene(0.30 g, 2.9 mmol, 30 equivalents per chain end) was dissolved inchlorobenzene (0.5 mL) and the reaction mixture heated at 125° C. for 24hours. The viscous solution was then precipitated twice into methanol(500 mL) followed by redissolution into dichloromethane (25 mL) andprecipitation into hexane (500 mL). The purified polymer was collectedby vacuum filtration and dried to give the ABA triblock copolymer,polystyrene-poly(fluorene)-polystyrene P5 as an off-white solid (0.45 g,82%); ¹H NMR (CDCl₃). δ0.70-0.80 and 1.0-1.1 (peaks due topoly(fluorene) n-hexyl substitutents, 1.40-2.20 (m, CH and CH₂ ofpolystyrene backbone and peak due to α-methylenes of n-hexylfluorenesubstituents)), 6.40-7.20 (m, ArH from poly(styrene) and poly(fluorene))and 7.50-7.80 (m, ArH from poly(fluorene)); GPC (PSt equivalent Mn=9500,PDI=1.62).

EXAMPLE 7 Macromolecular Initiation

[0070] Polymerization of TEMPO-functionalized poly(fluorene) P4 with4-vinyltriphenylamine, P6 (FIG. 3): A mixture of thealkoxyamine-substituted poly(di-n-hexylfluorene) P4 (Mn=5,000,PDI=1.80), (0.25 g, 0.05 mmol) and 4-vinyltriphenylamine (0.79 g, 2.9mmol, 30 equivalents per chain end) was dissolved in chlorobenzene (0.75mL) and the reaction mixture heated at 125° C. for 24 hours. The viscoussolution was then precipitated twice into methanol (250 mL) followed byredissolution into dichloromethane (10 mL) and precipitation into hexane(250 mL). The purified polymer was collected by vacuum filtration anddried to give the ABA triblock copolymer,poly(vinyltriphenylamine)-poly(di-n-hexylfluorene)-poly(vinyltriphenylamine)P6 as an off-white solid (0.93 g, 90%); ¹H NMR (CDCl₃). δ0.70-0.80 and1.0-1.1 (peaks due to n-hexyl substituents of the poly(fluorene)),1.40-2.20 (m, CH and CH₂ of poly(vinyltriphenylamine) backbone and peaksdue to the α-methyemes units of the n-hexyl substituents on thepoly(fluorene) units), 6.40-7.20 (m, ArH from poly(vinyltriphenylamine)and poly di-n-hexyl (fluorene)) and 7.50-7.80 (m, ArH from poly(di-n-hexyl (fluorene)); GPC (PSt equivalent Mn 10,500, PDI=1.68).

EXAMPLE 8 Polymerization with Macromolecular End Cappers

[0071] (a) Preparation of ABA Copolymer (P7) [85/15Poly(9,9-di-n-hexylfluorene-co-9,10-anthracene)] End Capped withPoly(2-styryl-5-2-5-p-methylphenyloxadiazole) (FIG. 4): Into a Schlenktube containing 242 mg (0.88 mmol) of bis(1,5-cyclooctadiene) nickel(0), 95 mg (0.88 mmol) of 1,5-cyclooctadiene and 137.3 mg (0.88 mmol) of2,2′-bipyridyl was placed 3 mL of dry DMF and 3 mL of toluene. Thesolution (blue) was heated to 80° C. for 0.5 hours and a degassedmixture of 200 mg (0.41 mmol) of 2,7-dibromo-9,9-di-n-hexylfluorene, 27mg (0.05 mmol) of 9,10-dibromoanthracene and 200 mg (0.07 mmol) of thebromophenyl-terminated polyoxadiazole P3 described previously (Mn=3000)in 3 mL of degassed toluene were added. Upon addition of the monomers,the reaction color turned reddish-brown and the mixture became moreviscous. The reaction mixture was heated for 24 h and the hot polymersolution precipitated into 105 mL of a equivolume mixture of conc HCl,methanol and acetone. After isolation of the polymer by filtration achloroform solution was reprecipitated into acetone/methanol: 286 mg,(83%), Mn=13,008, PDI=1.9. Based on GPC analysis, the Mn of the DHF/ANTblock was 7008 g/mol. ¹H NMR resonances for the aliphatic protons of theoxadiazole block were observed at δ1.4-2.2, and 2.4. The aliphaticresonances of the DHF units appeared at 0.75, 1.1 and 2.08. The combinedaromatic resonances of the block copolymer appeared as broad multipletsat δ6.31-8.10.

[0072] (b) Preparation of ABA Block Copolymer (P8) of 85/15Poly(9,9-di-n-hexyl fluorene-co-9,10-anthracene) End Capped with Poly(vinyl triphenylamine) (FIG. 5): This material was prepared as describedabove using the following quanitites: 190 mg (0.127 mmol) ofp-bromophenyl substituted poly(vinyl triphenylamine) PVTPA, P1 (Mn=1500g/mol), 541 mg (1.1 mmol) 2.7-dibromo-9,9-di-n-hexylfluorene, 51 mg(0.15 mmol) 9,10-dibromoanthracene, 632 mg (2.3 mmol)bis(1,5-pyclooctadiene) nickel (0), 248 mg (2.3 mmol)1,5-cyclooctadiene, 359 mg (2.3 mmol) bipyridyl in a mixture of 10 mL oftoluene and 5 mL of DMF. Reprecipitation yielded 489 mg (85%) of the ABAblocks copolymer P8; Mn=30,306, PDI-2.3, ¹H NMR resonances for the PVTPAblock were observed at δ1.40-2.20 and 6.50-7.20. The aliphaticresonances for the DHF units appeared at δ0.82, 1.17 and 2.10. Thearomatic resonances for the DHF and ANT units appear at δ7.27-8.0. Basedon GPC analysis with on polystyrene standards, the Mn of the DBF/ANTblock was ca 27,300 g/mol.

EXAMPLE 9 Preparation of Block-Graft Copolymers

[0073] (a) 2-7-Dibromo-9,9-bis(4-vinylphenyl)methyl)fluorene (BVPBr2F)(FIG. 6): 20.0 g (62 mmol) of 2,7-dibromofluorene and 22.9 g (150 mmol)of p-chloromethylstyrene were dissolved in 100 mL of toluene and 50 mLof NaOH (50 wt % in water) was added to the above solution. 0.1 g oftetra(n-butyl)ammonium bromide was added to the above mixture as a phasetransfer catalyst. The color of mixture turned dark brown as soon asphase transfer catalyst was added. The mixture was stirred at roomtemperature for 12 hours. Ethyl acetate was added and the organic phasewashed with water several times to remove NaOH. The organic layer wasdried over anhydrous magnesium sulfate and the solvent was removed byrotary evaporator. The product was obtained by precipitating againstn-hexane and methanol. The yield was 28 g (81%). ¹H NMR (CDCl₃)δ7.5-7.0(m, 6H), 6.9(d, 4H), 6.5(d, 4H), 6.5-6.3(q, 2H), 5.5(d, 2H),5.0(d, 2H), 3.2(s, 4H); ¹³C NMR (CDCl₃), δ150.1, 138.9, 136.5, 135.8,135.5, 130.5, 130.3, 127.8, 125.3, 121.3, 120.6, 113.2, 57.2, 45.0.

[0074] (b)1-((4-(2,7-dibromo-9-((4-(2,2,6,6-tetramethylpiperidyloxy)ethyl)phenyl)methyl)fluorene-9-yl)methyl)phenyl)ethoxy)-2,2,6,6-tetramethylpiperidine,(Br2BTFLUO) (FIG. 6): To a solution of BVPBr2F (15.0 g, 27 mmol) and2,2,6,6-tetramethylpiperidinyloxy (TEMPO) (24.0 g, 154 mmol) in 1:1toluene/ethanol (1000 mL) was added(N,N′-bis(3,5-di-tert-butylsalicylidene)-1,2-cycohexanediaminato)manganese (III) chloride (16.8 g, 26.5 mmol) followed by di-tert-butylperoxide (24 g, 164 mmol) and sodium borohydride (12 g, 316 mmol). Thereaction mixture was then stirred at room temperature for 16 hours,evaporated to dryness, partitioned between dichloromethane (250 mL) andwater (400 mL), and the aqueous layer further extracted withdichloromethane (3×250 mL). The combined organic layers were then dried,evaporated to dryness, and the crude product purified by flashchromatography eluting eith n-hexane:ethyl acetate (50:1). The desiredalkoxyamine was obtained as a white solid and the yield was 8.0 g (34%).¹H NMR (CDCl₃) δ7.5-7.1 (m, 6H), 6.9(d, 4H), 6.4(d, 4H), 4.5(q, 2H),3.3(s, 4H), 1.5-0.3(m, 42H); ¹³C NMR (CDCl₃) δ:150.4, 143.8, 138.8,134.7, 130.2, 129.8, 128.0, 126.9, 126.0, 121.0, 120.4, 82.9, 59.8,57.1, 44.8, 40.3, 34.2, 23.0, 20.3, 17.2; mp 65-67° C.

[0075] (c) Grafting Polystyrene on Br2BTFLUO, P9 (FIG. 7): Into a dryvial were introduced the initiator Br2BTFLUO (500 mg, 0.57 mmol),styrene (295 mg, 2.84 mmol) and acetic anhydride (400 mg. 3.9 mmol). Thesolution was degassed and sealed under argon before heating to 125° C.for 16 hours. The molecular weight of polystyrene could be controlled bythe feed ratio of styrene and the initiator. The polymer was dissolvedin chloroform and then precipitated into methanol. After filtering anddrying under vacuum, a white solid was obtained; (90%) Mn=5766,PDI=1.15; ¹H NMR (CDCl₃) δ0.9-2.5 (polystyrene and initiator aliphaticresonances), 3.2 (PhCH₂), 4.0 (CH₃ CHPh) 6.3-7.5 (polystyrene andinitiator aromatic resonances); Tg=100° C. (d) Yamamoto Polymerization(FIG. 8): The statistical copolymers P10 from2,7-dibromo-9,9-di-n-hexylfluorene and the 2,7-dibromofluorenecontaining polystyrene, P9, were synthesized through nickel (0) mediatedYamamoto polymerization. A Schienk tube containing 6 mL toluene, 6 mLDMF, bis(1,5-cyclooctadienyl) nickel (0) (460 mg, 1.67 mmol) and 261 mg(1.67 mmol) of 2,2′-bipyridyl and 1,5-cyclooctadiene (180 mg, 1.67 mmol)(molar ratios, 1:1:1) was heated under nitrogen to 80° C. for 0.5 hr.The monomers Br2DHF (443 mg, 0.9 mmol) and 577 mg (0.1 mmol) of P-9,molecular weight 1K, dissolved in 6 mL toluene were added to the abovesolution and the polymerization was maintained at 80° C. for 24 hours. 5Mol % of 2-bromo-9,9-di-n-hexylfluorene was added with monomers forend-capping. The polymer P10 was precipitated from an equivolume mixtureof conc. HCl, methanol and acetone. The isolated polymer was dissolvedin chloroform and re-precipitated in methanol-acetone (1:1). Finally,the polymer was dried at 60° C. under vacuum; 85%, Mn=23, 901, PDI=2.65,¹H NMR (CDCl₃) δ. 0.9-2.4 polystyrene and initiator core aliphaticresonances), 0.8, 1.2, 2.1 (DHF aliphatic resonances), 6.2- 7.2(polystyrene aromatic resonances), 7.5-8.0 (DHF aromatic resonances); Tg98° C.; λ_(max)(THF)=384 nm.

[0076] (e) Nickel-Mediated Copolymerization of Br2BTFLUO and Br2DHF, P11(FIG. 9): The statistical copolymers from 2,7-dibromo-9,9-di-n-hexylfluorene (Br2DHF) and the TEMPO-functionalized monomer Br2BTFLUO wereprepared as described. Into a Schlenk tube was placed 460 mg (1.67 mmol)of bis(1,5-cyclooctadiene) nickel (0), 261 mg (1.67 mmol) of bipyridyl,180 mg (1.67 mmol) of 1,5-cyclooctadiene in 12 mL of a 1:1 DMF/toluenesolvent mixture and the contents heated to 80° C. for 0.5 h. Then amixture of 418 mg (0.85 mmol) of 2,7-dibromo-9,9-di-n-hexylfluorene, 88mg (0.10 mmol) of the TEMPO-functionalized initiator Br2BTFLUO and 21 mg(0.05 mmol) of 2-bromo-9,9-di-n-hexylfluorene in 6 mL of toluene wasadded and the mixture heated at 80° C. for 24 h. The polymer wasprecipitated and purified as described previously. 82%, Mn=25,918,PDI=3.5; ¹H NMR (CDCl₃) 0.7-2.1 (aliphatic protons of DHF and initiatorunits), 6.8-7.9 (aromatic protons of DHF and initiator units), 3.5(PhCH₂—), 4.6 (CH₃CHO—); Tg-109° C.

[0077] (f) Graft Polymerization of Poly(styrene) to the Copolymer, P11;alternate preparation of P10: Into a flask with N₂ was placed 100 mg ofthe polymer P11 (90/10 DHF/BTLUO), 1.1 g of distilled styrene, and 10 mgof acetic anhydride, and the reaction mixture was heated to 125° C. for24 hr. The solution was precipitated into methanol followed byfiltration. The solid was redissolved in dichloromethane andreprecipitated into hexane to yield the purified polymer P10.

1. A dual purpose electroactive copolymer comprising a chargetransporting polymeric segment and a light emitting polymeric segment.2. The dual purpose electroactive copolymer of claim 1, comprising twoor more charge transporting polymeric segments.
 3. The dual purposeelectroactive copolymer of claim 2, comprising an A-B-A block copolymerin which each A represents a charge transporting polymeric segment and Brepresents the light emitting polymeric segment.
 4. The dual purposeelectroactive copolymer of claim 2, comprising a brush-type graftcopolymer having a backbone and pendant chains covalently bound thereto.5. The dual purpose electroactive copolymer of claim 4, wherein thelight emitting polymeric segment represents the backbone of thecopolymer, and the charge transporting polymeric segments represent thependant chains covalently bound thereto.
 6. The dual purposeelectroactive copolymer of claim 3, wherein the charge transportingpolymeric segments are comprised of arylamine monomer units.
 7. The dualpurpose electroactive copolymer of claim 5, wherein the chargetransporting polymeric segments are comprised of arylamine monomerunits.
 8. The dual purpose electroactive copolymer of claim 3, whereinthe charge transporting polymeric segments are comprised of conjugatedelectron-deficient monomer units.
 9. The dual purpose electroactivecopolymer of claim 5, wherein the charge transporting polymeric segmentsare comprised of electron-deficient or electron-rich monomer units. 10.The dual purpose electroactive copolymer of claim 8, wherein the monomerunits are selected from the group consisting of aryl sulfones, arylsulfoxides, fluorinated aryls, biphenyls, diaryl phosphine oxides,benzophenones, 1,2,3-triazole, 1,2,4-triazole, 1,2,3-oxadiazole,1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole,3,5-diaryl-1,2,4-oxadiazole, 3,4-diaryl-1,2,5-oxadiazole,2,5-diaryl-1,3,4-oxadiazole, 1,4-oxazine, 1,2,5-oxathiazine,benzothiophene, 2,5-diaryl oxadiazoles, thiophene, benzothiophene,pyridines, quinolines, quinoxalines, and pyrimidines.
 11. The dualpurpose electroactive copolymer of claim 10, wherein the monomer unitscomprise substituted ethylene units—CH_(2—CHR— in which R is selected from the group consisting of aryl sulfones, aryl sulfoxides, fluorinated aryls, biphenyls, diaryl phosphine oxides, benzophenones,)1,2,3-triazole, 1,2,4-triazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole,1,2,5-oxadiazole, 1,3,4-oxadiazole, 3,5-diaryl-1,2,4-oxadiazole,3,4-diaryl- 1,2,5-oxadiazole, 2,5-diaryl-1,3,4-oxadiazole, 1,4-oxazine,1,2,5-oxathiazine, 2,5-diaryl oxadiazoles, pyridines, quinolines,quinoxalines, and pyrimidines.
 12. The dual purpose electroactivecopolymer of claim 3, wherein the light emitting polymer segment iscomprised of polycyclic aromatic monomer units.
 13. The dual purposeelectroactive copolymer of claim 5, wherein the light emitting polymersegment is comprised of polycyclic aromatic monomer units.
 14. The dualpurpose electroactive copolymer of claim 12, wherein the polycyclicaromatic monomer units are fluorescent.
 15. The dual purposeelectroactive copolymer of claim 13 wherein the polycyclic aromaticmonomer units are fluorescent.
 16. The dual purpose electroactivecopolymer of claim 14, wherein the polycyclic aromatic monomer unitscomprise fluorene or a derivative thereof.
 17. The dual purposeelectroactive copolymer of claim 15, wherein the polycyclic aromaticmonomer units comprise fluorene or a derivative thereof.
 18. The dualpurpose electroactive copolymer of claim 16, wherein the polycyclicaromatic monomer units each comprise a 9,9-dialkylfluorene moiety, andfurther wherein each such moiety is bound through its 2-position to afirst adjacent monomer unit and through its 7-position to a secondadjacent monomer unit.
 19. The dual purpose electroactive copolymer ofclaim 17, wherein the polycyclic aromatic monomer units each comprise afluorene moiety, wherein at least some of the moieties are bound throughtheir 9-position to one or two of the pendant chains.
 20. A process forpreparing a dual purpose electroactive copolymer comprised of chargetransport polymeric segments and a light emitting polymeric segment,which comprises: (a) contacting a dihalo-substituted polycyclic aromaticreactant with a living free radical polymerization initiator underconditions effective to bring about polymerization, resulting in a lightemitting polymeric intermediate comprised of linked polycyclic aromaticmonomer units and two or more displaceable termini; and (b) synthesizinga charge transport polymeric segment comprised of polymerized chargetransporting monomer units at each of the displaceable termini, vialiving free radical polymerization.
 21. The process of claim 20, whereinthe polymeric intermediate contains two displaceable termini, and thedual purpose electroactive copolymer is an A-B-A block copolymer inwhich each A represents a charge transporting polymeric segment and Brepresents the light emitting polymeric segment.
 22. The process ofclaim 20, wherein the polymeric intermediate contains more than twodisplaceable termini, and the dual purpose electroactive copolymer is abrush-type graft copolymer having a backbone and pendant chainscovalently bound thereto.
 23. The process of claim 22, wherein the lightemitting polymeric segment represents the backbone of the copolymer, andthe charge transporting polymeric segments represent the pendant chainscovalently bound thereto.
 24. The process of claim 21, wherein thecharge transporting polymeric segment is comprised of arylamine monomerunits.
 25. The process of claim 23, wherein the charge transportingpolymeric segment is comprised of arylamine monomer units.
 26. Theprocess of claim 21, wherein the aromatic monomer units in thelight-emitting polymeric segment are electron-deficient orelectron-rich.
 27. The process of claim 23, wherein the aromatic monomerunits in the light-emitting polymeric segment are electron-deficient orelectron-rich.
 28. The process of claim 26, wherein theelectron-deficient or electron-rich monomer units are selected from thegroup consisting of aryl sulfones, aryl sulfoxides, fluorinated aryls,biphenyls, diaryl phosphine oxides, benzophenones, 1,2,3-triazole,1,2,4-triazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole,1,3,4-oxadiazole, 3,5-diaryl-1,2,4-oxadiazole,3,4-diaryl-1,2,5-oxadiazole, 2,5-diaryl-1,3,4-oxadiazole, 1,4-oxazine,1,2,5-oxathiazine, 2,5-diaryl oxadiazoles, pyridines, quinolines,quinoxalines, and pyrimidines.
 29. The process of claim 27, wherein theelectron-deficient or electron-rich monomer units are selected from thegroup consisting of aryl sulfones, aryl sulfoxides, fluorinated aryls,biphenyls, diaryl phosphine oxides, benzophenones, 1,2,3-triazole,1,2,4-triazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole,1,3,4-oxadiazole, 3,5-diaryl-1,2,4-oxadiazole,3,4-diaryl-1,2,5-oxadiazole, 2,5-diaryl-1,3,4-oxadiazole, 1,4-oxazine,1,2,5-oxathiazine, benzothiophene, 2,5-diaryl oxadiazoles, thiophene,benzothiophene, pyridines, quinolines, quinoxalines, and pyrimidines.30. The process of claim 21, wherein the polycyclic aromatic monomerunits are fluorescent.
 31. The process of claim 23, wherein thepolycyclic aromatic monomer units are fluorescent.
 32. The process ofclaim 30, wherein the polycyclic aromatic monomer units comprisefluorene or a derivative thereof.
 33. The process of claim 31, whereinthe polycyclic aromatic monomer units comprise fluorene or a derivativethereof.
 34. The process of claim 21, wherein the polycyclic aromaticmonomer units each comprise a 9,9-dialkylfluorene moiety, and furtherwherein, following step (a), each such moiety is bound through its2-position to a first adjacent monomer unit and through its 7-positionto a second adjacent monomer unit.
 35. The process of claim 23, whereinthe polycyclic aromatic monomer units each comprise a fluorene moiety,and further wherein, following step (a), at least some of the moietiesare bound through their 9-position to one or two of the pendant chains.36. The process of claim 20, wherein step (a) is conducted catalyticallyusing a metal catalyst.
 37. The process of claim 36, wherein the metalcatalyst is nickel or a salt or complex thereof.
 38. The process ofclaim 37, wherein the metal catalyst is bis(1,5-cyclooctadiene) nickel(0).
 39. The process of claim 20, wherein step (a) is conducted in thepresence of a living free radical polymerization initiator.
 40. Theprocess of claim 39, wherein the living free radical polymerizationinitiator comprises a TEMPO-containing monoarylhalide.
 41. The processof claim 40, wherein the living free radical polymerization initiatorcomprises 1-((4-bromophenyl)ethoxy)2,2,6,6-tetramethylpiperidine.
 42. Aprocess for preparing a dual purpose electroactive copolymer comprisedof charge transport polymeric segments and a light emitting polymericsegment, which comprises: (a) contacting a unimolecular living freeradical polymerization initiator with a polymerizable reactant underpolymerization conditions, wherein the initiator, the reactant, and thepolymerization conditions are effective to provide a charge transportingpolymeric intermediate comprised of a plurality of linked monomer unitsand a single reactive terminus; and (b) catalytically polymerizing adihalo-substituted polycyclic aromatic reactant in the presence of thecharge transporting polymeric intermediate, whereby a light emittingpolymeric segment comprised of linked polycyclic aromatic monomer unitsis formed, with two or more charge transporting polymeric segments boundthereto.
 43. In an opto-electronic device comprising a substrateprovided with an electroactive polymeric material on the surfacethereof, the improvement comprising employing as the electroactivepolymeric material the dual purpose electroactive copolymer of claim 1.44. In an opto-electronic device comprising a substrate provided with anelectroactive polymeric material on the surface thereof, the improvementcomprising employing as the electroactive polymeric material the dualpurpose electroactive copolymer of claim
 3. 45. In an opto-electronicdevice comprising a substrate provided with an electroactive polymericmaterial on the surface thereof, the improvement comprising employing asthe electroactive polymeric material the dual purpose electroactivecopolymer of claim
 5. 46. The opto-electronic device of claim 43,comprising a light-emitting diode.
 47. The opto-electronic device ofclaim 44, comprising a light-emitting diode.
 48. The opto-electronicdevice of claim 45, comprising a light-emitting diode.